Release Notes

[Unreleased]

New features

  • FFT spectral solver for 1-D and 2-D problems. Exact for periodic boundaries; other boundary conditions are handled with 4α zero-padding (NoOutsideLoads approximation). Requires scalar (uniform) elastic thickness. In-plane stresses (sigma_xx, sigma_yy, sigma_xy) are fully supported.

  • YAML configuration file format alongside the legacy INI format. Pass a .yaml / .yml file to the CLI or to the F1D / F2D constructor.

  • Domain-padding utilities to reduce spurious boundary effects when using spatially variable elastic thickness:

    • 2-D: pad_domain, smooth_pad_Te, recommended_pad_width

    • 1-D: pad_domain_1d, smooth_pad_Te_1d, recommended_pad_width_1d

  • FD boundary-condition warnings — F1D and F2D now issue UserWarning messages for '0Moment0Shear' (free broken end — verify a rifted margin is intended), '0Slope0Shear' (no clear geological analog), and when the nearest loaded cell is within one flexural wavelength of a '0Displacement0Slope' boundary (forebulge suppression).

Improvements

  • Iterative FD solver (Solver = iterative) upgraded from Jacobi to ILU preconditioning; falls back to a direct solve if LGMRES does not converge. The ConvergenceTolerance parameter is now passed as rtol (relative residual) to SciPy’s LGMRES; default remains 1e-3.

  • In-plane membrane stresses (sigma_xx, sigma_yy, sigma_xy) now supported by all FD and FFT solvers in both 1-D and 2-D.

Bug fixes

  • Fixed 2-D FD constant-Te stencil: corrected dx/dy swap, σ swap, and missing /dx² factors that produced incorrect results for asymmetric grids.

  • Fixed 2-D FFT sigma_xy assembly: double-wrapped corner entries and wrong coefficient in the Periodic right-roll buffer.

  • Fixed 0Slope0Shear description in configuration reference and README.

Documentation

  • New Sphinx / Read the Docs site with a theory page (governing equations, solution methods, in-plane stresses), an accuracy page, a configuration reference, API reference, and changelog.

  • Theory page covers the full governing PDE with in-plane stress terms for both 1-D and 2-D, the variable-D FD expansion, and the FFT transfer function.

Tests

  • Comprehensive new test suites for 1-D SAS/SAS_NG, 2-D SAS/SAS_NG, 1-D FFT, 2-D FFT (including sigma_xy), 1-D FD boundary conditions with analytical cross-validation, 2-D FD, FD boundary-condition warnings, and all domain-padding utilities.

1.3.0 - 2026-05-27

  • New: BmiGflex — CSDMS Basic Model Interface (BMI) v2 implementation; bmipy is an optional dependency and gFlex works without it.

  • New: F1D, F2D, and BmiGflex are now accessible directly from the gflex package namespace (e.g. import gflex; gflex.F2D()); previously this raised AttributeError.

  • Fix: updated scipy.sparse.linalg import for compatibility with modern scipy.

  • Fix: latent typo self.T_e → self.Te in the scalar-Te branch of get_coeff_values (introduced 2021-06-26); would produce incorrect results when tectonic stress terms (sigma_xx, sigma_yy, sigma_xy) are non-zero.

  • Removed outdated root-level gflex_bmi.py.

1.2.0 - 2024-01-08

  • Python 3 modernisation: black formatting, isort, updated imports, argparse CLI, pyproject.toml replacing setup.py.

  • GitHub Actions CI replacing Travis CI.

  • Eric W. H. Hutton added as author.

1.1.1 - 2021-06-26

  • Updated PyPI support: twine upload, README.md

  • Throw meaningful error if a nonuniform self.Te grid is used with the analytical solution

1.1.0 - 2018-05-28

  • Support for both Python 2 and Python 3

  • Main code

  • Examples

  • README.md updates

  • PATH updates in

  • Code tests included

  • Code testing on commit by Travis

  • Updated on PyPI

1.0.1 - 2018-05-25

  • Final Python 2 (only) release

  • Additional documentation added

1.0.0 - 2017-05-10

This is the update is what is available now from pypi.

  • Minor updates to the main gFlex codes

  • Addition of a missing “12” in the flexural wavelength calculator in the utilities.

1.0 - 2016-01-28

  • First full release of gFlex in association with the now-accepted GMD paper, “Open-source modular solutions for flexural isostasy: gFlex v1.0”, by A. D. Wickert.

0.9 - 2015-03-05

  • Release submitted to GMD and that appears on PyPI; this is the same as v1.0a on umn-earth-surface.

0.8.1 - 2015-03-04

  • Fixed error in PyPI integration from v0.8 and updated README.md to include PyPI integration.

0.8 - 2015-03-04

  • First fully-functional and error-checked release, and therefore the first true non-“pre-release”.

0.7 - 2015-01-21

This release may be short-lived, but is the turning point at which work on gFlex will go from fixing deficiencies to adding new capabilities. As such, it is receiving version 0.7 (the last version of its parent project, “Flexure”, was 0.6 back in 2012). It now seems to be functional and stable, and thus this tagged release will be the basis for this stage of the model to be pulled to @csdms-contrib and @umn-earth-surface.